1. Technical Field
The present application relates to a method for making carbon nanotube field emitter.
2. Discussion of Related Art
Many potential applications have been proposed for carbon nanotubes, including conductive and high-strength composites, energy storage and energy conversion devices, sensors, field emission displays, and nanometer-sized semiconductor devices.
A method for making a field emission electron source is taught by U.S. Pat. No. 7,988,515 to Wei et al. The method includes steps of: (a) providing a CNT array; (b) drawing a bundle of CNTs from the CNT array to form a CNT film; (c) soaking the CNT film in an organic solvent, and shrinking the CNT film into a CNT string after the organic solvent volatilizing; (d) applying a voltage between two opposite ends of the CNT string, until the CNT string snaps at a certain point; and (e) attaching the snapped CNT string to a conductive base, and achieving a field emission electron source.
However, a field emitter of carbon nanotube array is made by a plurality of the snapped CNT strings, the snapped CNT strings are difficult to manipulate and be mass produced in a large quantity. Furthermore, it is difficult to make the distance between adjacent snapped CNT strings uniform, which affects field emission efficiency of the field emitter.
What is needed, therefore, is to provide a method for making carbon nanotube field emitter with high field emission efficiency, and the method should be easy to operate and able to mass produce the carbon nanotube field emitters.